Histology of Gut Flashcards
what are the 4 histoligical layers of the digestive system?
- Mucosa (epithelium, lamina propria, muscularis mucosae)
- Submucosa (CT with BV, lymph vessels and nerves)
- Muscularis propria (peristalsis)
- Adventitia or serosa (depending whether it is in peritoneal cavity or not)
what are the two muscularis layers found in the digestive system?
which one is on outside / inside?
- *longitudinal muscle:** outside
- *circular muscle:** inside
what are the 6 layers of the oesophagus? what find in them?
- mucosa: non-keratiniised stratified squamous epithelium
2. lamina propria: BV, inflam cells, mucus glands
3. muscularis mucosa: thin layer of smooth muscle
4. submucosa: DICT, blood and lymph vessels, nerve fibres, Meissners plexus
5. muscularis externa / propria: top 1/3: skeletal -> for swallowing, bottom 1/3: smooth muscle -> peristalsis
6 adventita: loose CT, BV, adipose
- how does the muscarlis externa / propria change in the oesphagus?
- what does the oesophagus look like take cross section?
- which nerve plexuses do u find in the oesphagus? (2) and where do find them?
1. muscarlis externa / propria:
top 1/3 made from skeletal muscle = swallowing
bottom 1/3 made from smooth muscle = peristalsis
- cross section: **looks collapsed
3.**
nerve plexi:
- meissner plexus: submucosal tissue
- auerbach’s plexus: myenteric - betweeen circ and long. muscle layer
where in the oesphagus would this image be taken?
which type of muscle is on the left / right?
in the middle: when both skeletal and smooth muscle exist (skeletal on left, smooth on right)
what is the squamocolumnar junction? - change
squamocolumnar junction
- abrupt change in the mucosa from stratified squamous to columnar cells (and glands)
- Oesophagus joins at an acute angle
- only the mucosa changes, the underlying layers stay the same !!
label a-e
what is the main histological feature of the stomach? (2)
what are their roles?
what are the different types of gastric glands in the stomach?
main histological feature: gastric pits (picture 1) and gastric glands (picture 2) in the mucosa
gastric pits; secrete bicarbonate ions which protect the epithelium from acidic gastric juice
gastric glands:
- body and fundus:
- transitional zones - cardiac and pyloric glands:
cardia and pyloric mucosa:
- where find?
- cell types?
- function?
- what are nuclei like?
cardia and pyloric mucosa:
-
location
i) cardia: start / oesph -> stomach
ii) pyloric: end / stomach -> duo
- cell types: columnar epithelium - mucous secreting cells
- function: protec the oesphageal epithelium and pyloric mucosa against gastric juices
- nuceli: small & close to basal domain
name the 5 different types of celsl find in the body / fundic mucosa?
body / fundic mucosa:
- branched tubular glands: produce gastric juice
- mucous neck cells: secrete mucous
- chief cells: deep at bottom of fundic glands. secrete pesinogen !
- parietal cells: neck of fundic segment: secrete HCl and intrinsic factor !
- stem cells
- endocrine cells
which cells in stomach secrete:
- *- pepsinogen?
- HCl?**
where in the stomach do u find them?
how do u differientate? (2)
- pepsinogen: chief cells
- HCl: parietal cells
- chief cells: deep in fundic glands
- parietal cells: neck of fundic segment
- chief cells: smaller, paler
- parietal cells: bigger, darker
label these cells of stomach xox
- in the small intestine, enzymes are secreted by small intestinal cells called?
- what are the folds called in the small intestine?
- what are the main histological feature of small intestine? (2)
- what are the lieberkuhns crpyts?
- in the small intestine, enzymes are secreted by small intestinal cells called enterocytes
- what are the folds called in the small intestine: plicae circularis
- what are the main histological feature of small intestine: villi (projections of the mucosa) & microvilli
- lieberkuhns crpyts: gland found in between villi
label these layers of the small intestine
what is the GALT?
what does it include (3)
gut assocaited lymphatic tissue
includes:
- peyers patches of small intestine (groupings of lymphoid follicles in the mucus membrane that lines your small intestine)
- lymphatic circ supplying immune cells
- lymphoid aggregrates in large intestine
- intra-epthilial lymphocytes: found inbetwen epi cells
- dentritic cells: grab antigens and take to lymph nodes
what are the three zones of the anal canal? what are the cells like there?
what happens to circular muscle in anal canal?
what happens to long muscle in anal canal?
- *colorectal zone:** simple columnar epi
- *anal transitional zone:** transition betwen simple columnar and and stratified squamous epi
- *squamous zone:** stratified squamous
circ muscle: becomes internal anal sphincter
long muscle: extends over sphincter & attaches to CT
